Urinary incontinence is a major health care problem in the United States and an area of high priority for NIDDK. This DK55387 competitive renewal grant will explore several new developments using muscle derived stem cells (MDSC) as a treatment of stress urinary incontinence. We were extremely productive during the initial ROl grant funding period and we would like to thank NIDDK for their support. All key objectives of the previous grant were successfully completed. This resulted in 7 peer review papers, 3 more manuscripts are in press and 3 are near completion and will be submitted. Our findings were publicized at 16 international meetings and through 24 submitted abstracts. As a result of our work, we won 3 international contests and submitted 3 patents. A NTDDK Ki 2 Physician Scientist fellow, 3 PhDs. 2 Ph.D. candidates and 3 medical students entering urology worked on our project. Among them are 3 women (1 African American) and 2 African American men. What questions have been left unresolved? The experiments during the present grant identified new issues. We have evidence that bladder injection of MDSC rather than myoblasts persist in the bladder up to 6 months. MDSC can differentiate into smooth muscle. Most importantly, MDSC were able to improve the contractility of damaged bladder muscle while myoblasts were not. In the renewal grant, we want to investigate several important issues, such as: 1. Will MDSC injection improve function in a damaged urethral sphincter? 2. What is the potential for MDSC to differentiate into neurons and improve urologic function? 3. If MDSC becomes neurons, what neurons do they become, afferent, sympathetic, and/or parasympathetic? 4. Do MDSC become neurons in normal conditions or under conditions of acute or chronic stress and neuropathy? The Key Aims of this grant include: 1. Evaluation of the long-term safety and persistence of allogenic MDSC versus myoblasts urethral injection, 2. Measure urethral MDSC injection to improve sphincter function by assessing leak point pressure (LPP) and urethral strip contractility, 3. Assessment of MDSC ability to improve peripheral nerve functions and differentiate into neurons, and 4. Isolation, purification, and proliferation of human MDSC that would be suitable for clinical trial. We want to strongly emphasize that our stem cell research is in complete compliance with the federal guideline on embryonic stem cell research. We want to underscore that these stem cells have not been obtained from embryos (animal or human) or cell lines of embryonic stem cells.